ACK: [SRU][Q][PATCH 0/1] CVE-2026-53043

[Tim Whisonant]

On Fri, Jul 17, 2026 at 01:56:33AM +0300, Cengiz Can via kernel-team wrote:
> https://ubuntu.com/security/CVE-2026-53043
> 
> [ Impact ]
> 
> In dlm_match_regions(), the qr_numregions field from a DLM_QUERY_REGION network
> message is used directly as loop bounds without validation against
> O2NM_MAX_REGIONS. The o2net layer only validates message byte length, not field
> values, so a crafted message can set qr_numregions up to 255 and trigger out-
> of-bounds reads past the 1024-byte qr_regions buffer, which is sized for at
> most 32 entries. This can be exploited remotely to leak memory or crash the
> node.
> 
> [ Fix ]
> 
> questing: clean cherry-pick
> focal: clean cherry-pick
> bionic: clean cherry-pick
> xenial: clean cherry-pick
> trusty: clean cherry-pick
> 
> [ Test Plan ]
> 
> Boot tested.
> 
> [ Where Problems Could Occur ]
> 
> A regression in the ocfs2/dlm subsystem could reject legitimate
> DLM_QUERY_REGION messages or otherwise disrupt region matching during DLM node
> join, potentially preventing cluster nodes from joining the domain.
> 

Acked-by: Tim Whisonant <tim.whisonant at canonical.com>